<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<input type="text" v-model="h" placeholder="身高">
<input type="text" v-model="w" placeholder="体重">
<input type="button" value="计算" @click="f1()">

<h2>{{info}}</h2>

<script src="https://cdn.bootcdn.net/ajax/libs/axios/0.21.1/axios.min.js"></script>
<script src="https://cdn.staticfile.org/vue/2.2.2/vue.min.js"></script>
<script>
  let v =new Vue({
    el:"body>div",
    data:{
        h:"",
        w:"",
      info:""
    },
    methods:{
        f1(){
            axios.get("/bmi?h="+v.h+"&w="+v.w).then(function (response) {
            alert(response.data);
          })
        }
    }
  })
</script>
</body>
</html>